Fix suggestion to deference reference index

Code

fn main() {
    let i = 0 as usize;
    let arr = [false];
    println!("{}", arr[&i]);
}

Current output

--> src/main.rs:4:24
    |
  4 |     println!("{}", arr[&i]);
    |                        ^^ slice indices are of type `usize` or ranges of `usize`
    |
    = help: the trait `SliceIndex<[bool]>` is not implemented for `&usize`
help: `usize` implements trait `SliceIndex<T>`
   --> /home/moosama76/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/slice/index.rs:179:1
    |
179 | const unsafe impl<T> SliceIndex<[T]> for usize {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `SliceIndex<[T]>`
    |
   ::: /home/moosama76/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/bstr/traits.rs:197:1
    |
197 | unsafe impl SliceIndex<ByteStr> for usize {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `SliceIndex<ByteStr>`
    = note: required for `[bool]` to implement `Index<&usize>`
    = note: 1 redundant requirement hidden
    = note: required for `[bool; 2]` to implement `Index<&usize>`
help: dereference this index
    |
  4 |     println!("{}", arr[*&i]);
    |                        +

Desired output

help: remove the reference, 
  |
4 |     println!("{}", arr[&i]);
    |                      -

Rationale and extra context

I want to improve this diagnostic

Other cases

Rust Version

rustc 1.98.1 (48a229cea 2026-09-01)
binary: rustc
commit-hash: 48a229ceaefd4985c50990b14116b6d856af0985
commit-date: 2026-09-01
host: x86_64-unknown-linux-gnu
release: 1.98.1
LLVM version: 22.1.8

Anything else?

No response

Reproduce the example in src/main.rs with rustc 1.98.1 and compare the current indexing diagnostic with the desired output. Trace the compiler diagnostic handling for the reference index case; the work is done when it suggests removing the reference and shows the requested source replacement.